Laboratory incubators usually serve to store samples, more particularly, biological and/or microbiological samples, in the internal chamber thereof, under predefined conditions such as specific temperature and humidity conditions and, in the case of gassing incubators, a defined gas atmosphere. In such situations, the attempt is usually made to imitate the conditions of the human or animal body. Frequently, selected conditions are therefore a temperature of approximately 37° C. and an optimally high humidity level of generally at least 60%, preferably, at least 80% and, more preferably, at least 90%, without, however, allowing condensation of moisture to take place on the walls or other regions of the incubator. Such regions of moisture present potential contamination centers.
A number of options are known in the prior art for the creation of a humid atmosphere in the internal chamber of a laboratory incubator. A first such option is the provision of a water reservoir inside the incubator, from which reservoir water is vaporized by means of heating (see, EP 1552888 A2). This option, however, presents a major problem in the form of the ease of contamination of the water bath and the risk of contamination of the samples stored in the incubator.
For the purpose of ensuring an even distribution of temperature and moisture content in the internal chamber, the air in the internal chamber is usually circulated by means of a fan. This often involves conducting the air evenly across the entire internal chamber upwardly from the floor toward the ceiling with the air being conducted across the water bath mounted on the floor, where it absorbs moisture and conveys the same into the internal chamber. A fan is disposed at the ceiling and is adapted to suck in the air and conduct it through a duct located between the outer and inner housings, thus, causing it to flow back toward the floor along the ceiling and side wall (see, U.S. Pat. No. 6,878,177 B2 and U.S. Pat. No. 6,333,004 B1). However, such ventilation in the internal chamber bears the risk of the samples stored therein becoming desiccated or contaminated by germs entrained from the water bath. Furthermore, an issue occurs when starting up the incubator or after opening the door and, thus, disturbing the atmosphere of the internal chamber in that a relatively long period of time before the levels of moisture content and temperature in the internal chamber reach or return to the desired level.
There has thus been a certain demand for a laboratory incubator that allows for the storage of samples in its internal chamber at a highly constant level of moisture content and with the least possible risk of contamination or desiccation. It is an object of the present invention to provide such a laboratory incubator.